Novel photographic products and processes



Feb. 11, 1969 D o ET AL 3,427,158

NOVEL PHOTOGRAPHIC PRODUCTS AND PROCESSES Filed June 2, 1966 7{5%L%'E35TXYEE'LVER \-INTERL AYER 25 i 1 mAsEuTA DYE DEVELOPER LAYER \N \\\\\{R%Eg.ss-sms MR mTE'RLAYER I .YELLow DYE DEVELOPER LAYER L EkLLJESSKEJIS[FA\;ERSILVER HALIDE -OVERCOAT LAYER 1 f-I-I-l-l-f-I-EI-Ii-I-Q AQUEOUS ALKALINE PROCESSING COMPOSITION 23 -NEUTRALIZING LAYER INVENTOR @amdfizf/awn United States Patent 17 Claims The present invention relates to photography and, more particularly, to photographic products particularly adapted for employment in photographic diffusion transfer color processes.

The primary objects of the present invention are to provide photographic products, particularly adapted for employment in diffusion transfer photographic color processes; to provide photographic products which include a photosensitive element which comprises a plurality of essential layers including, superposed on a common support, at least two selectively sensitized photosensitive strata each having associated therewith, as color transfer image-forming components, a dye of predetermined color which is a silver halide developing agent, at least one of said photosensitive strata comprising gelatin, wherein at least two of said sensitized strata and associated dye are separated .from each other by a layer comprising a polymer containing a diffusible gelatin hardening agent substantially inert with respect to said polymer as further specified hereinafter; to provide photographic diffusion transfer products comprising a photosensitive element, of the last-identified type, in combination with a photographic diffusion transfer image-receiving element comprising a plurality of essential layers including a common support carrying a solution dyeable polymeric layer; and to provide photographic diffusion transfer color processes employing photosensitive film units including, in combination, a photosensitive element and a transfer imagereceptive element of the last-identified types, and a fluid photographic transfer processing composition.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the product possessing the features, properties and the relation of components and the process involving the several steps and the relation and order of one or more of such steps with respect to each of the others which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing, wherein the figure detailed is a diagrammatic enlarged cross-sectional view illustrating the association of elements during one stage of the performance of a diffusion transfer process, for the production of a multicolor positive transfer print, the thickness of the various materials being exaggerated.

As disclosed in US. Patent No. 2,983,606, issued May 9, 1961, a photosensitive element containing a dye developer, that is, a dye which is a silver halide developing agent, and a silver halide emulsion may be exposed and wetted by a liquid processing composition, for example, by immersion, coating, spraying, flowing, etc., in the dark, and the exposed photosensitive element is superposed prior to, during, or after wetting, on a sheetlike support element which may be utilized as an image-receiving element. In a preferred embodiment, the liquid processing composition is applied to the photosensitive element in a substantially uniform layer as the photosensitive element is brought into superposed relationship with the image-receiving layer. The liquid processing Patented Feb. 11, 1969 "ice composition, positioned intermediate the photosensitive element and the image-receiving layer, permeates the emulsion to initiate development of the latent image contained therein. The dye developer is immobilized or precipitated in exposed areas as a consequence of the development of the latent image. This immobilization is apparently, at least in part, due to a change in the solubility characteristics of the dye developer upon oxidation and especially as regards its solubility in alkaline solutions. It may also be due in part to a tanning effect on the emulsion by oxidized developing agent, and in part to a localized exhaustion of alkali as a result of development. In unexposed and partially exposed areas of the emulsion, the dye developer is unreacted and diffusible and thus provides an imagewise distribution of unoxidized dye developer dissolved in the liquid processing composition, as a function of the point-to-point degree of exposure of the silver halide emulsion. At least part of this imagewise distribution of unoxidized dye developer is transferred, by imbition, to a superposed image-receiving layer or element, said transfer substantially excluding oxidified dye developer. The image-receiving element receives a depthwise diffusion, from the developed emulsion, of unoxidized dye developer without appreciably disturbing the imagewise distribution thereof to provide the reversed or positive color image of the developed image. The image-receiving element may contain agents adapted to mordant or otherwise fix the diffused, unoxidized dye developer. If the color of the transferred dye developer is affected by changes in the pH of the image-receiving element, this pH may be adjusted in accordance with well-known techniques to provide a pH affording the desired color. The desired positive image is revealed by stripping the image-receiving layer from the photosensitive element at the end of a suitable imbition period.

The dye developers, as noted above, are compounds which contain, in the same molecule, both the chromophoric system of a dye and also a silver halide developing function. By a silver halide developing function is meant a grouping adapted to develop exposed silver halide. A preferred silver halide development function is a hydroquinonyl group. Other suitable developing functions include ortho-dihydroxyphenyl and orthoand paraamino substituted hydroxyphenyl groups. In general, the development function includes a benzoid developing function, that is, an aromatic devolping group which forms quinonoid or quinone substances when oxidized.

Multicolor images may be obtained using color imageforming components such as, for example, the previously mentioned dye developers, in diffusion transfer processes by several techniques. One such technique contemplates obtaining multicolor transfer images utilizing dye developers by employment of an integral multilayer photosensitive element, such as is disclosed in the aforementioned US. Patent No. 2,983,606, and particularly with reference to FIG. 9 of the patents drawing, wherein at least two selectively sensitized photosensitive strata, superposed on a single support, are processed, simultaneously and without separation, with a single, common image-receiving layer. -A suitable arrangement of this type comprises a support carrying a red-sensitive silver halide emulsion stratum, a green-sensitive silver halide emulsion stratum and a blue-sensitive silver halide emulsion stratum, said emusions having associated therewith, respectively, for example, a cyan dye developer, a magenta dye developer and a yellow dye developer. The dye developer may be utilized in the silver halide emulsion layer, for example, in the form of particles, or it may be employed as a layer behind the appropriate silver halide emulsion strata. Each set of silver halide emulsion and associated dye developer strata are disclosed to be optionally separated from other sets by suitable interlayers, for example, by a layer of gelatin or polyvinyl alcohol. In certain instances, it may be desirable to incorporate a yellow filter in front of the green-sensitive emulsion and such yellow filter may be incorporated in an interlayer. However, where desirable, a yellow dye developer of the appropriate spectral characteristics and present in a state capable of functioning as a yellow filter may be employed. vIn such instances, a separate yellow filter may be omitted.

The dye developers are preferably selected for their ability to provide colors that are useful in carrying out subtractive color photography, that is, the previously mentioned cyan, magenta and yellow. The dye developers employed may be incorporated in the respective silver halide emulsion or, in the preferred embodiment, in a separate layer behind the respective silver halide emulsion. Specifically, the dye developer may, for example, be in a coating or layer behind the respective silver halide emulsion and such a layer of dye developer may be applied by use of a coating solution containing about 0.5 to 8%, by weight, of the respective dye developer distributed in a film-forming natural, or synthetic, polymer, for example, gelatin, polyvinyl alcohol, and the like, adapted to be permeated by the chosen diffusion transfer fluid process ing composition.

An extensive compilation of specific dye developers particularly adapted for employment in photographic diffusion transfer processes is set forth in aforementioned U.S. Patent No. 2,983,606 and in the various copending U.S. applications referred to in that patent, especially in the table of U.S. applications incorporated by reference into the patent as detailed in column 27. As examples of additional U.S. Patents detailing specific dye developers for photographic transfer rocess use, mention may also be made of U.S. Patents Nos. 2,983,605, 2,992,106 3,047,386, 3,076,808, 3,076,820, 3,077,402, 3,126,280, 3,131,061, 3,134,762, 3,134,765, 3,135,604, 3,135,605, 3,135,606, 3,135,734, 3,141,772, 3,142,565, and the like.

As additional examples of synthetic, film-forming, permeable polymers particularly adapted to retain dispersed dye developer, mention may be made of nitrocarboxymethyl cellulose, as disclosed in U.S. Patent No. 2,992,104; an acylamidobenzene sulfo ester of a partial sulfobenzal of polyvinyl alcohol, as disclosed in U.S. Patent No. 3,043,692; polymers of N-alkyl-a,B-unsaturated cavboxamides and copolymers of N-alkyl-u, 3-carboxamides with N-hydroxyalkyl-ot,B-unsaturated carboxamides, as disclosed in U.S. Patent No. 3,069,263; copolymers of vinyl-phthalimide and a,,8-unsaturated carboxylic acids, as disclosed in U.S. Patent No. 3,061,428; copolymers of N-vinylpyrrolidones and cap-unsaturated carboxylic acids and terpolymers of N-vinylpyrrolidones, a,fi-unsaturated carboxylic acids and alkyl esters of 01,13- unsaturated carboxylic acids, as disclosed in U.S. Patent No. 3,044,873; copolymers of N,N-dialkyl-a,[3-unsaturated carboxamides with a, 3-unsaturated carboxylic acids, the corresponding amides of such acids, and copolymers of N-aryland N-cycloalkyl-afi-unsatumted carboxamides with a,/3-unsaturated carboxylic acids, as disclosed in U.S. Patent No. 3,069,264; and the like.

In addition to conventional techniques for the direct dispersion of a particulate solid material in a polymeric, or colloidal, matrix such as ball-milling and the like techniques, the preparation of the dye developer dispersion may also be obtained by dissolving the dye in an appropriate solvent, or mixture of solvents, and the resultant solution distributed in the polymeric binder, with optional subsequent removal of the solvent, or solvents, employed, as, for example, by vaporization where the selected solvent, or solvents, possesses a sufficiently low boiling point or washing where the selected solvent, or solvents, possesses a sufficiently high differential solubility in the wash medium, for example, water, when measured against the solubility of the remaining composition components,

and/ or obtained by dissolving both the polymeric binder and dye in a common solvent.

For further detailed treatment of solvent distribution systems of the types referred to above, and for an extensive compilation of the conventional solvents traditionally employed in the art to effect distribution of photographic color-providing materials in polymeric binders, specifically for the formation'component layers of photographic film units, reference may be made to U.S. Patent Nos. 2,269,158, 3,322,027, 2,304,939, 2,304,940, 2,801,171, and the like.

Copending U.S. application Ser. No. 234,684, now U.S. Patent No. 3,362,819 filed Nov. 1, 1962, in the name of Edwin H. Land discloses image-receiving elements, particularly adapted for employment in the preceding diffusion transfer processes, which comprise a support layer possessing on one surface thereof, in sequence, a polymeric acid layer, preferably an inert timing or spacer layer, and an image-receiving layer adapted to provide a visible image upon transfer to said layer of diffusible dye image-forming substance.

As set forth in the last-mentioned application, the polymeric acid layer comprises polymers which contain acid groups, such as carboxylic acid and sulfonic acid groups, which are capable of forming salts with alkali metals, such as sodium potassium, etc., or with organic bases, particularly quaternary ammonium bases, such as tetramethyl ammonium hydroxide, or potentially acidyielding groups, such as anhydrides or lactones, or other groups which are capable of reacting with bases to capture and retain them. The acid-reacting group is, of course, nondiifusible from the acid polymer layer. In the preferred embodiments disclosed, the acid polymer contains free carboxyl groups and the transfer processing composition employed contains a large concentration of sodium and/ or potassium ions. The acid polymers stated to be most useful are characterized by containing free carboxyl groups, being insoluble in water in the free acid form, and by forming water-soluble sodium and/or potassium salts. One may also employ polymers containing carboxylic acid anhydride groups, at least some of which preferably have been converted to free carboxyl groups prior to imbibition. While the most readily available polymeric acids are derivatives of cellulose or of vinyl polymers, polymeric acids from other classes of polymers may be used. As examples of specific polymeric acids set forth in the application, mention may be made of dibasic acid half-ester derivatives of cellulose which derivatives contain free carboxyl groups, e.g., cellulose acetate hydrogen phthalate, cellulose acetate hydrogen glutarate, cellulose acetate hydrogen succinate, ethyl cellulose hydrogen succinate, ethyl cellulose acetate hydrogen succinate, cellulose acetate hydrogen succinate hydrogen phthalate; ether and ester derivatives of cellulose modified with sulfoanhydrides, e.g., with ortho-sulfobenzoic anhydride; polystyrene sulfonic acid; carboxymethyl cellulose; polyvinyl hydrogen phthalate; polyvinyl acetate hydrogen phthalate; polyacrylic acid; acetals of polyvinyl alcohol with carboxyor sulfo-substituted aldehydes, e.g., o-, m-, or p-benzaldehyde sulfonic acid or carboxylic acid; partial esters of ethylene/maleic anhydride copolymers; partial esters of methylvinyl ether/maleic anhydride copoly-mers; etc.

The acid polymer layer is disclosed to contain at least sufficient acid groups to effect a reduction in the pH of the image layer from a pH of about 13 to 14 to a pH of at least 11 or lower at the end of the imbibition period, and preferably to a pH of about 5 to 8 within a short time after imbibition. As previously noted, the pH of the processing composition preferably is of the order of at least 13 to 14.

It is, of course, necessary that the action of the polymeric acid be so controlled as not to interfere with either development of the negative or image transfer of unoxidized dye developers. For this reason, the pH of the image layer is kept at a level of pH 12 to 14 until the positive dye image has been formed after which the pH is reduced very rapidly to at least about pH 11, and preferably about pH 9 to 10, before the positive transfer image is separated and exposed to air. Unoxidized dye developers containing hydroquinonyl developing radicals diffuse from the negative to the positive as the sodium or other alkali salt. The diffusion rate of such dye image-forming components thus is at least partly a function of the alkali concentration, and it is necessary that the pH of the image layer remain on the order of 12 to 14 until transfer of the necessary quantity of dye has been accomplished. The subsequent pH reduction, in addition to its desirable effect upon image light stability, serves a highly valuable photographic function by substantially terminating further dye transfer. The processing technique thus effectively minimizes changes in color balance as a result of longer imbibition times in multicolor transfer processes using multilayer negatives.

In order to prevent premature pH reduction during transfer processing, as evidenced, for example, by an undesired reduction in positive image density, the acid groups are disclosed to be so distributed in the acid polymer layer that the rate of their availability to the alkali is controllable, e.g., as a function of the rate of swelling of the polymer layer which rate in turn has a direct relationship to the diffusion rate of the alkali ions. The desired distribution of the acid groups in the acid polymer layer may be effected by mixing the acid polymer with a polymer free of acid groups, or lower in concentration of acid groups, and compatible therewith, or by using only the acid polymer but selecting one having a relatively lower proportion of acid groups. These embodiments are illustrated, respectively, in the cited copending application, by (a) a mixture of cellulose acetate and cellullose acetate hydrogen phthalate and (b) a cellulose acetate hydrogen phthalate polymer having a much lower percentage of phthalyl groups, than the first-mentioned cellulose acetate hydrogen phthalate.

It is also disclosed that the layer containing the polymeric acid may contain a water insoluble polymer, preferably a cellulose ester, which acts to control or modulate the rate at which the alkali salt of the polymer acid is formed. As examples of cellulose esters contemplated for use, mention is made of cellulose acetate, cellulose acetate butyrate, etc. The particular polymers and combinations of polymers employed in any given embodiment are, of course, selected so as to have adequate wet and dry strength and when necessary or desirable, suitable subcoats may be employed to help the various polymeric layers adhere to each other during storage and use.

The inert spacer layer of the aforementioned copending application, for example, an inert spacer layer comprising polyvinyl alcohol or gelatin, acts to time control the pH reduction by the polymeric acid layer. This timing is disclosed to be a function of the rate at which the alkali diffuses through the inert spacer layer. It was stated to have been found that the pH does not drop until the alkali has passed through the spacer layer, i.e., the pH is not reduced to any significant extent by the mere diffusion into the interlayer, but the pH drops quite rapidly once the alkali diffuses through the spacer layer.

As examples of materials, for use as the image-receiving layer, mention may be made of solution dyeable polymers such as nylons as, for example, N-methoxymethyl polyhexamethylene adipamide; partially hydrolyzed polyvinyl acetate; polyvinyl alcohol with or without plasticizers; cellulose acetate with filler as, for example, onehalf cellulose acetate and one-half oleic acid; gelatin; and other materials of a similar nature. Preferred materials comprise polyvinyl alcohol or gelatin containing a dye mordant such as poly-4-vinylpyridine, as disclosed in the copending US. application of Howard C. Haas, Ser. No.

6 50,848, filed Aug. 22, 1960, now US. Patent No. 3,148,- 061, issued Sept. 8, 1964.

As disclosed in the previously cited patents, the liquid processing composition referred to for effecting multicolor diffusion transfer processes comprises at least an aqueous solution of an alkaline material, for example, diethylamine, sodium hydroxide or sodium carbonate and the like, and preferably possessing a pH in excess of 12. Where this liquid processing composition is to be applied to the photo-sensitive emulsion stratum by being spread thereon, preferably in a relatively thin and uniform layer intermediate that stratum and a superposed image-receiving layer, it is disclosed to include a viscosity-increasing compound constituting a film-forming material of the type which, when the composition is spread and dried, forms a relatively firm and relatively stable film. The preferred film-forming materials disclosed comprise high molecular weight polymers such as polymeric, water-soluble ethers which are inert to an alkaline solution such as, for example, a hydroxyethyl cellulose or sodium carboxymethyl cellulose. Additionally, film-forming materials or thickening agents whose ability to increase viscosity is substantially unaffected if left in solution for a long period of time are also disclosed to be capable of utilization. As stated, the film-forming material is preferably contained in the processing composition in such suitable quantities as to impart to the composition a viscosity in excess of cps. at a temperature of approximately 24 C. and preferably in the order of 100,000 cps. to 200,000 cps. at that temperature.

For the production of the photoresponsive gelatino silver halide emulsions employed to provide the film unit, the silver halide crystals may be prepared by reacting a water-soluble silver salt, such as silver nitrate, with at least one water-soluble halide, such as ammonium, potassium or sodium bromide, preferably together with a corresponding iodide, in an aqueous solution of a peptizing agent such as a colloidal gelatin solution; digesting the dispersion at an elevated temperature, to provide increased crystal growth; washing the resultant dispersion to remove undesirable reaction products and residual water-soluable salts by chilling the dispersion, noodling the set dispersion, and washing the noodles with cold water, or, alternatively, employing any of the various flocc systems, or procedures, adapted to effect removal of the undesired components, for example, the procedures described in US. Patents Nos. 2,614,928; 2,614,929; 2,728,- 662; and the like; after-ripening the dispersion at an elevated temperature in combination with the addition of gelatin and various adjuncts, for example, chemical sensitizing agents of US. Patents Nos. 1,574,944; 1,623,499; 2,410,689; 2,597,856; 2,597,915; 2,487,850; 2,518,698; 2,521,926; and the like; all according to the traditional procedures of the art, as described in Neblette, C. B, Photography Its Materials and Processes, 6th Ed, 1962.

Optical sensitization of the emulsions silver halide crystals may be accomplished by contact of the emulsion composition with an effective concentration of the selected optical sensitizing dyes dissolved in an appropriate dispersing solvent such as methanol, ethanol, acetone, water, and the like; all according to the traditional procedures of the art, as described in Hammer, F. M., The Cyanine Dyes and Related Compounds.

Additional optional additives, such as coating aids, hardeners, viscosity-increasing agents, stabilizers, preservatives, and the like, for example, those set forth hereinafter, also may be incorporated in the emulsion formulation, according to the conventional procedures known in the photographic emulsion manufacturing art.

The photoresponsive material of the photographic emulsion will, as previously described, preferably comprise a crystal of silver, for example, one or more of the silver halides such as silver chloride, silver iodide, silver bromide, or mixed silver halides such as silver chlorobromide or silver iodobromide, of varying halide ratios and varying silver concentrations.

The emulsions may include the various adjuncts, or addenda, according to the techniques disclosed in the art, such as speed-increasing compounds of the quaternary ammonium type, as described in U.S. Patents Nos. 2,271,- 623; 2,288,226; and 2,334,864; or of the polyethyleneglycol type, as described in U.S. Patent No. 2,708,162; or of the preceding combination, as described in U.S. Patent 'No. 2,886,437; or the thiopolymers, as described in U.S. Patents Nos. 3,046,129 and 3,046,134. The emulsions may also be stabilized with the salts of the noble metals such as ruthenium, rhodium, palladium, iridium rand platinium, as described in U .8. Patents Nos. 2,566,245 and 2,566,263; the mercury compounds of U.S. Patents Nos. 2,728,663, 2,728,664 and 2,728,665; the triazoles of U.S. Patent No. 2,444,608; the azindines of U.S. Patents Nos. 2,444,605, 2,444,606, 2,444,607, 2,450,397, 2,444,609, 2,713,541, 2,743,181, 2,716,062, 2,735,769, 2,756,147, 2,772,164; and those disclosed by Burr in Zwiss. Pot, vol. 47, 1952, pp 228; the disulfides of Belgian Patent No. 569,317; the benzothiazolium compounds of U.S. Patents Nos. 2,131,038 and 2,694,716; the zinc and cadmium salts of U.S. Patent No. 2,839,405; and the mercapto compounds of U.S. Patent No. 2,819,965.

Hardening agents such as inorganic agents providing polyvalent metallic atoms, specifically polyvalent aluminum or chromium ions, for example, potash alum and chrome alum [K Cr (S0 -24H O] and inorganic agents of the aldehyde type, such as formaldehyde, glyoxal, mucochloric, etc.; the ketone type such as diacetyl; the quinone type; and the specific agents described in U.S. Patents Nos. 2,080,019, 2,725,294, 2,725,295, 2,725,305, 2,726,162, 2,732,316, 2,950,197, and 2,870,013 may be incorpora ted, Where desired, in the selected coating solution compositions.

Coating solution compositions employed to fabricate the respective strata of the film unit may contain one or more coating aids such as saponin; a polyethyleneglycol of U.S. Patent No. 2,831,766; a polyethyleneglycol ether of U.S. Patent No. 2,719,087; a taurine of U.S. Patent No. 2,739,891; a maleopimarate of U.S. Patent No. 2,823,123; an amino acid of U.S. Patent No. 3,038,804; a sulfosuccinamate of U.S. Patent No. 2,992,108; or a polyether of U.S. Patent No. 2,600,831; or a gelatin plasticizer such as glycerin; a dihydroxyalkane of U.S. Patent No. 2,960,- 404; a bis-glycolic acid ester of U.S. Patent No. 2,904,434; a succinate of U.S. Patent No. 2,940,854; or a polymeric hydrosol of U.S. Patent No. 2,852,386.

As the binder for the respective emulsion strata, the aforementioned gelatin may be, in whole or in part, replaced with some other colloidal material such as albumin; casein; or zein; or resins such as a cellulose derivative, as described in U.S. Patents Nos. 2,322,085 and 2,327,808; polyacryl'amides, as described in U.S. Patent No. 2,541,474; vinyl polymers such as described in U.S. Patents Nos. 2,253,078, 2,276,322, 2,276,323, 2,281,703, 2,310,223, 2,311,058, 2,311,059, 2,414,208, 2,461,023, 2,484,456, 2,538,257, 2,579,016, 2,614,931, 2,624,674, 2,632,704, 2,642,420, 2,678,884, 2,691,582, 2,725,296, 2,753,264, and the like.

It has now quite unexpectedly been discovered that if the integral multilayer photosensitive element, described above, is specifically fabricated to comprise, in combination, a support layer, at least two selectively sensitized silver halide emulsion layers each having a dye, which dye is a silver halide developing agent, of predetermined color associated therewith, at least one of said emulsion layers comprising gelatin, and a layer, intermediate said emulsion layers, comprising a processing composition permeable polymer containing a diffusible gelatin hardening agent substantially inert with respect to said polymer, significant improvement may be achieved with respect to the elements color isolation and potential photographic process speed, and with respect to the brilliance, density and hue of the transfer image color characteristics.

Specifically, employment of the detailed polymeric interlayer, containing a difiusible gelatin hardening agent substantially inert with respect to the polymer comprising the interlayer, facilitates the fabrication of, and employment of, an integral multilayer photosensitive element comprising ultrathin gelatin strata, preferably a plurality of ultrathin gelatin strata as emulsion and/or dye retaining strata and the like, by providing the requisite dimensional stability to the gelatin strata necessary to maintain the integral multilayer elements structural integrity, during the above-described diffusion transfer processing, when such gelatin layers are of a sufliciently thin magnitude, individually and/or in combination, as to cause a loss of transfer image definition in the absence of the instant specified structure. The employment of the designated ultra-thin gelatin strata provides the concomitant results of adducing significantly higher transfer process speed, higher transfer image maximum densities, greater cyan and magenta dye saturation, and improved red and blue hues, in addition to improved photosensitive interimage eifects.

The instant invention is thus directly concerned with a photosensitive element which comprises a common support having, positioned on one surface, at least two selectively sensitized photosensitive silver halide emulsion strata, preferably, having predominant sensitivity to separate regions of the spectrum, each having a dye of predetermined color associated therewith, for example, a spectral absorption range substantially complementary to the predominant sensitivity range of the associated emulsion, Which dye is a silver halide developing agent, that is, a dye developer, separated by a spacer or interlayer comprising a processing composition permeable polymer containing a diflusible gelatin hardening agent substantially inert with respect to the polymer matrix.

The spacer, or interlayer, permeable polymer employed may comprise any one or more of the processing composition permeable polymeric interlayer compositions of the art such as, for example, the so-called barrier system interlayers disclosed in copending U.S. application Ser. No. 565,135, filed June 29, 1965, now abandoned in the names of Edwin H. Land and Howard G. Rogers. The barrier type interlayers set forth in the last cited applica tion comprise, with the exception of compositions which react with the diifusible gelatin hardening agent to prevent its diffusion as, for example, gelation retaining or type interlayer compositions, in general, a polymeric layer which is permeated, by the fluid processing composition, at a rate sufiiciently slow as to insure that permeation of the fluid composition, from an outer emulsion layer into the next inner emulsion layer, is deferred, until processing of the outer emulsion layer is substantially complete. In general, as disclosed in the last-cited application, barrier layers of the type therein designated comprise two distinct classes. The first type comprises initially impermeable polymeric interlayers which possess a solution rate, upon contact with the fluid processing composition, during photographic processing, such that the interlayer requires a longer time span to be rendered permeable than the time interval necessitated to efiect development of the outer emulsion strata. The second type comprises initially impermeable polymeric interlayers which possess a hydrolysis rate, upon contact with the fiuid processing composition, such that the interlayer requires a time interval for the occurrence of hydrolysis, sufficient as to processing composition permeability, in excess of that required to eifect development of the outer emulsion.

Preferably, however, the polymer comprising the barrier, or interlayer, will comprise a processing composition permeable and hydratable polymer having a dye pemeable lattice substantially only in the hydrated state and a hydration rate less than the development and greater than the fogging rate of the respective dye associated silver halide emulsion possessing the slowest development and most rapid fogging as disclosed in U.S. application Ser. No. 486,862, filed Sept. 13, 1965, in the name of Richard J. Haberlin.

As examples of such preferred polymers, mention may be made of vinyl acetate-crotoni-c acid copolymer containing less than about crotonic acid, by Weight, preferably about 1 to 3% crotonic acid, by weight; isopropyl cellulose, preferably about 1.3 :05 isopropyl groups per cellulosic monomer unit; hydroxypropyl methyl cellulose, preferably containing 1.5 $0.3 methoxyl groups per cellulosic monomer unit, and the like.

In general, the selected preferred polymer is aqueous alkaline solution permeable and hydratable, most preferably, substantially instantaneously permeable by solution retained molecules having a geometric size less than the geometric size of the transfer image-forming dye, such as, for example, auxiliary silver halide developing agents, antifoggants, accelerators, arrestors, and the like, in order that photographic development, and the like, may proceed with respect to the emulsion next adjacent the film base, with the earliest time sequence possible. The preferred polymer is thus positioned to effect simultaneously retardation of the rearward diffusion of the dye associated with the silver halide emulsion next adjacent the photosensitive elements surface and the forward diffusion of the dye associated with the silver halide emulsion next adjacent the film base, until the respective imagewise emulsion development and control of each dye is substantially established, and insured. There is thus provided by selection of a polymer, within the stated preferred class, an effective restriction of each dyes developing function to the specific silver halide emulsion with which it is associated, and thereby color isolation selectively determined by the incident spectral energy distribution, per unit area, of the respective photoresponsive silver halide emulsions exposure.

In the preferred embodiment, each of the photoresponsive silver halide emulsion strata comprising the integral multilayer photosensitive element specifically employs gelatin as the colloid binder for the respective emulsions photoresponsive silver halide grains, or crystals. Most preferably the integral multilayer photosensitive element comprises a tripack configuration containing, on one surface of a support, a red-sensitive gelatino silver halide emulsion having associated therewith cyan dye developer, a green-sensitive gelatino silver halide emulsion having associated therewith magenta dye developer intermediate the red-sensitive gelatino silver halide emulsion layer and a blue-sensitive gelatino silver halide emulsion layer having associated therewith yellow dye developer most distant from the support surface, wherein the desig nated interlayer is present intermediate at least two of said emulsion layers.

Most preferably, the respective cyan, magenta and yellow dye developers are each dispersed in a separate gelatin layer next adjacent its associated gelatino silver halide emulsion layer, intermediate the emulsion layer and the support, and a separate interlayer is present intermediate both the blue sensitive gelatino silver halide emulsion/yellow dye developer and the green-sensitive gelatino silver halide emulsion/magenta dye developer units, and the red-sensitive gelatino silver halide emulsion/cyan dye developer and the green-sensitive gelatino silver halide emulsion/magenta dye developer units, at least one of the interlayers comprising a polymeric layer of the present invention.

In the last described embodiment of the present invention, preferably, the gelatin layers comprise ultra-thin gelatin layers and specifically, the gelatino silver halide emulsion layers are not greater than about 3 microns thick, the dye retaining gelatin layers are not greater than about 5 microns thick and the polymer interlayers are not greater than about 3 microns in thickness. in the preferred tripack structure detailed above, the total thickness of the respective emulsions, gelatino-dye retaining layers, and the polymeric interlayers will not exceed 30 microns. With respect to a preferred image-receiving element, the image-receiving layer is about 0.25 to 0.4 mils thick, the polymer acid layer is about 0.3 to 1.5 mils thick, and the spacer layer is about 0.1 to 0.7 mil thick. It will be specifically recognized that the relative dimensions recited above with respect to polymeric interlayers and the layers of the preferred image-receiving elements layers may be appropriately modified, in accordance with the desires of the operator, with respect to the specific product to be ultimately prepared. However, increasing the relative dimensions of the gelatino silver halide emulsion layers and the dye retaining gelatin layers, above the parameters set forth, will, in general, progressively detract from the specifically advantageous photographic results achieved by employment of the present photosensitive elements structure in accordance with the respective magnitude of the increase employed.

Although substantially any difiusible gelatin hardening agent may be distributed in and diffused from the polymeric interlayer in accordance with the practice of the present invention, it will be readily recognized that the hardening agent selected should not provide deleterious photographic effects and, with that exception, substantially any of the extensive plurality of hardening agents known to effect hardening of the protein gelatin may be suitably employed. A multiplicity of hardening agents are disclosed in the prior art as specifically adapted to effect hardening of photographic gelatin compositions and accordingly are to be preferred. As examples of hardening agents contemplated for employment in the practice of the present invention, mention may be made of: the dialdehydes such as glyoxal and mesoxal dialdehyde of U.S. Patent No. 1,870,354; and the derivatives of such compounds as disclosed in U.S. Patent No. 1,- 941,852; the hydroxyaldehydes or aldoses up to and including the pentoses and hydroxydialdehyde and hydroxy aldehyde ketones such as glycol aldehyde, glyceric aldehyde, erythritose, arabinose, tartaric dialdehyde, hydroxy pyroracemic aldehyde, and their isometric forms, of U.S. Patent No. 2,059,817; the dialkyl, diaryl, or alkaryl diketones such as diacetyl, acetyl caproyl, and acetyl benzoyl, of U.S. Patent No. 2,063,351; the aldehyde carboxylic acids such as glyoxalics acid, glyoxyl propionic acid, glyoxyl isobutyric acid, formyl acrylic acid, formyl acetic acid, B-formyl propionic acid, and 'y-formyl butyric acid, of U.S. Patent No. 2,154,895; the chloro-acetones of U.S. Patent No. 2,169,513; the acetals of aliphatic aldehydes such as fi-ethoxyacrolein, glyoxal, acetylene dialdehyde, and the like, for example, [i-ethoxyacrolein acetal, glyoxal tetramethyl acetal, glyoxal tetraethyl acetal, and acetylene dialdehyde tetramethyl acetal, of U.S. Patent No. 2,172,300; the hydroxyketones such as dihydr-oxyacetone, p-hydroxybenzoylcarbinol, 2,4,6-trihydroxybenzoylcarbinol, 3keto-butane-l-ol, propionylearbinol, 3-keto-pentan-1-ol, hydroxy-methylene-acetone, fructose, and sorbinose, of U.S. Patent No. 2,180,335; the amino-substituted aldehydes such as piperidino acetic aldehyde, diethyl amino acetic aldehyde, and amino acetaldehyde, of U.S. Patent No. 2,247,569; the unsaturated aliphatic, 1,4-diketones such as diacyl ethylene, dipropionyl ethylene, and acetylpropionyl ethylene, of U.S. Patent No. 2,344,013; the nitro aldehydes such as nitro-propandial and nitrolactic aldehyde, of U.S. Patent No. 2,- 372,873; the primary aliphatic nitro alcohols such as 2- nitro-1,3-propanediol, 2-methyl-2-nitro-1-propanol, 2- ethyl-2-nitro-1,3-propanediol, tris-(hydroxymethyl)-nitromethane, and 2-nitro-1-butanol, of U.S. Patent No. 2,- 494,055; dimethylol-diketopiperazines such as 1,4-dimetl1- ylol-2,5-diketopiperazine, 1,4-dimethyl-3,6-dimethyl-2,5- diketopiperazine, 1,4 dimethylol-3,6-di-isopropyl-2,5-cliketopiperazine, 1,4-dimethylol-3,6-di-isobutyl-2,S-diketopiperazine, and 1,4-dimethylol-3,6-diphenyl-2,5-diketopiperazine, of U.S. Patent No. 2,586,168; the keto alco- 1 l hols such as 3-ketobutanol, 2-methyl-3-ketobutanol, 2,2- dimethylol-3-butanone, and 2-methyl-3-ketopentanol, of U.S. Patent No. 2,629,659; the polyanhydrides such as 7,8 diphenylbicyclo (2,2,2) 7 octene-2,3,5,6-tertatcarboxylic dianhydride of U.S. Patent No. 2,725,294; the cyclic 1,2-diketones such as cyclohexane-1,2-dione, cyclopentane-1,2 dione, and 3-chloro-cyclopentanes-1,2-dione of U.S. Patent No. 2,725,305; the bis-esters of methane sulfonic acid such as 1,2-di-(methanesulfonic acid)- ethane, 1,3 di (methanesulfanoxy)-propane, 1,5-di- '(methanesulfanoxy) pentane, and ,B,B-di-(methane-sulfanoxy)-diethyl ether of U.S. Patent No. 2,726,162; the 1,3rdihydroxymethylbenzimidazol-Z-one of the U.S. Patent No. 2,732,316; the 2,3-dihydroxy dioxane of U.S. Patent No. 2,870,013; the aziridinyl sulfonyls such as l,3-bis-(l-aziridinylsulfonyl) propane and l-(l-aziridinylcarbonyl)-3-(l-aziridinylsul-fony) benzene of U.S. Patent No. 2,964,404; the aziridine compounds such as N,N'- trimethylene-bis-(l-aziridine-carboxamide), N,N' octamethylene-bis-( l-aziridine-carboxamide) toluene-2,4-bis- (l-aziridine-carboxamide), and N,N-tetramethylene-bis- (l-aziridinecarboxamide), of U.S. Patent No. 2,950, 197; the 1,3,5-tris(halogenacetyl) perhydro-1,3,5-triazines such as 1,3,5 tris(chloroacetyl)perhydro-1,3,5-triazine,1,3,5- tris(bromoacetyl)-perhydro-1,3,5-triazine, and 1,3,5-tris (iodoacetyl)perhydro-1,3,5-triazine, of U.S. Patent No. 2,976,152; the his and tris aziridinyl azines of U.S. Patent No. 2,983,611; the aromatic divinyl sulfones such as 1,3- di(vinyl-sulfonyl)-benzene, 1 methyl-2,4-di-(vinyl-sulfonyl -benzene, 1-methyl-3 ,5 -di- (vinyl-sulfonyl) -benzene, 1,3-dimethyl-4,6-di-(vinyl-sulfonyl)-benzene, 1,3,5 trimethyl-2,4-di- (vinyl-sulfonyl) -benzene, 1,3 ,5 ,6-tetrametl1- y1-2,4-di(vinyl-sulfonyl) -benzene, 1,3,5-tri- (vinyl-sulfonyl) -benzene, l-rnethyl-2,4,6-tri- (vinyl-sulfonyl -benzene benzene-1,3-disulfonic acid-di (4-vinyl-sulfonyl -anilide, benzene-1,3-disulfonic acid-di-(3'-vinyl-sulfonyl)-anilide, 1,3-dimethy1-benzene-4,6-disulfonic acid-di-(4-vinyl-sulfonyl)-anilide, and l,3-dimethyl-benzene-4,6-disul'fonic acid-di(3'-vinyl-sulfonyl)-anilide, of U.S. Patent No. 2,- 994,611; the oxysaccharides such as oxysucrose and oxyot-methyl-D-glucoside of U.S. Patent No. 3,034,894; the oxystarches of U.S. Patent No. 3,057,723; the N-arylvinylsulfonamides such as vinyl sulfonic acid anilide, vinyl sul-fonic acid-p-phenetide, vinyl sulfonic acid-p-toluidide, vinyl sulfonic acid-N-methyl anilide, and vinyl sulfonic acid-m-chloro anilide of U.S. Patent No. 3,061,436; the N ,N-disubstituted carbodiimides such as N-isopropyl- N-(4-dimethylaminophenyl)car-bodiimide ethyl p-toluenesulfonate, N-phenyl-N'-(4-dimethylaminophenyl)carbodiimide ethyl p-toluenesulfonate, N,N-di(4-dimethy1- aminophenyl)carbodiimide monoethobromide, N,N'-di(4- dimethylaminophenyl)carbodiimide monoethiodide, N, N di(4-dimethylaminophenyl)carbodiimide dimethiodide, N,N-di(4-diethylaminophenyl)carbodiimide methyl p-toluenesulfonate, N,N '-di (4-dipropylaminotolyl) carbodiimide ethyl p-toluenesulfonate, N,N-di(4-dimethylaminophenyl)carbodiimide monomethosulfate, N,N-di(4-dimethylaminophenyl)carbodiimide dimethosulfate, N,N'- di(4-dimethylaminophenyl)carbodiimide ethyl p-toluenesulfonate, N-bornyl-N-(4-dimethylaminophenyl) carbodiimide methosulfate, N-menthyl-N-(4-dimethylaminopheny1)carbodiimide ethosulfate, N (fi-bromoallyl)-N- -dimethylaminopropyl)carbodiimide ethosulfate, N- (tert.-butyl) N (-y-dimethylaminopropyl)carbodiimide ethyl p-toluenesulfonate, N cyclohexyl-N-(4-dimethylaminophenyl)carbodiimide ethyl p-toluenesulfonate, N- isopropyl N ('y-dimethylaminopropyl)carbodiimide ethobromide, N-methoxymethyl-N-('y-dimethylaminopropyl)carbodiimide ethyl p-toluenesulfonate, N,N'-di-( pyridyl)carbodiimide monomethosulfate, and N,-N'-di- -pyridyDcarbodiimide diethosulfate, of U.S. Patent No. 3,100,704; the organic diisocyanates such as tolyl diisocyanate, octamethylene diisocyanate, and hexamethylene diisocyanate, of U.S. Patent No. 3,103,437; bis-chloroethylureas such as 1,3-bis(2-chloroethyl)urea, N,N'-bis 12 r (2-chloroethyl-carbamyl)-1,6-hexanediamine, and N,N- bis(2-chloroethyl-carbamyl)ethylenediamine, of U.S. Patent No. 3,106,468; the amino-phosphoryl-halides such as dimethylaminophosphoryldichloride, and bisdimethylaminophosphorylchloride, of U.S. Patent No. 3,125,449; the sulfofluorides such as m-fluorosulfonyl benzoic acid, N-m-fiuorosulfonylphenyl amino acetic acid, p-fluorosulfonyl cinnamic acid, m-fiuorosulfonyl salicylic acid, N-rnfluorosulfonylphenyl-m-sulfamoyl benzoic acid, N-(mfluorosulfonyD-benzoyl anthranilic acid, m-fluorosulfonyl succinic acid anilide, p-fluorosulfonyl maleic acid anilide, m-fluorosulfonyl itaconic acid anilide, m-fluorosulfonyl phenoxyacetic acid, and m-(o-carboxyphenoxycarbonyl)- fluorosulfonylbenzene, of U.S. Patent No. 3,149,974; the chloroacylamidos such as bis-chloroacetyl-N,N'-dimethylethylenediamine, bis-chloroacetyl-ethylenediamine, and bis-chloroacetyl-1,2-phenylenediamine-4-carboxylic acid, of U.S. Patent No. 3,174,861; the fluorosulfonyls such as N-2-ch1oropropionyl-m-fluorosulfonylanilide, m fluorosulfonyl fenacylbromide, N-chloroacetyl-m-fluorosulfonyl anilide, N-chlorornethylsulfonyl-m-fluorosulfonyl anilide, and N-bromoacetyl-m-fluorosulfonyl anilide, of U.S. Patent No. 3,186,847; the phosphonitrile dichlorides of U.S. Patent No. 3,186,848; the imidazolones such as 1,3- bismorpholinomethyl benzimidazolone, 1,3 bispiperidinomethyl-5-chloro-benzimidazolone, 1,3 bispiperidinomethyl-S-chloro-benzimidazolone, 1,3 bisdiethylaminomethyl 4,S-benzo-benzimidazolone, 1,3 bispiperidinomethyl S-methoxybenzimidazolone, 1,3 bispiperidinomethyl-S-phenyl-benzimidazolone, l,3-bispiperidinometh yl-4,S-benzo-benzimidazolone, 1,3-bispiperidinomethyl-5- nitro-benzimidazolone, 1-hydroXymethyl-3-diethylaminomethyl-benzimidazolone, and 1,3-bismorpholinomethyl-4, S-pyridine-(2,3)-imidazolone, of U.S. Patent No. 3,- 207,604; and the like.

Preferably, the hardening agent, or agents, selected should be relatively rapid acting hardening agents which are substantially stable during storage of the photographic film unit retaining same. Specifically preferred are the aldehyde hardening agents, succindialdehydes and mucochloric acid.

The concentration of hardening agent employed, as known in the art, is dependent upon the relative activity of the selected agent, or agents, and the relative amount of gelatin to be hardened. The specific concentration of a selected hardening agent desired to be disposed in a selected polymeric binder may be readily determined empirically by the following technique. A particularly apt and simple empirical method, within the context of the ultimate photographic employment, has been found to comprise the rapid and simple procedure of microtoming a 5-micron cross section of the integral multilayer structure, mounting same on a microscope slide which had previously been coated with a thin layer of microscope objective immersion oil, covering the microtome section with a cover slip, and inducing alkali solution, to the contact edge of this section, by capillary action. The elfective activity of the selected hardening agent and the employed concentration, within the context of its ultimate usage, may then be visually recorded and correlated timewise with respect to maintenance of the dimensional stability of the resultant microtome section accomplished -by the selected hardening agent and chosen concentration. The correlation may be directly drawn from the visually observed swelling and delamination characteristics of the respective gelatin layers comprising the integral multilayer structure per unit time.

Although the art specifically states, that is, in U.S. Patent application Ser. No. 565,135, supra, that except in the lowest, that is, the innermost emulsion layer, it is undesirable that the carrier or binder material of the silver halide emulsion be rendered impermeable as by tanning,

hardening, etc., in that such hardening of the emulsion prevents, or retards, color-providing substances from diffusing outwardly from unexposed areas of an inner layer,

or layers, it has been specifically found that the hardening, or tanning, provided by the instant structure provides the advantageous results detailed throughout the specification, when the gelatin layers possess the specific thickness parameters identified. Specifically, it has been further found that when an integral multilayer photosensitive element, of the type detailed herein, possessing the designated plurality of ultrathin gelatin layers as set forth, is employed that an increase in maximum dye density is unexpectedly obtained as a function of and concomitant with the effected decrease in the relevant swelling capacity of the individual gelatin containing layers, in concert with the resultant decrease in the total layer thickness of the entire element.

In accordance with the teachings of the art, the positioning of the respective silver halide emulsion/dye de-' veloper units of the tripack configuration detailed above may be varied. However, as previously mentioned, it is generally preferred to constitute the tripack configuration in accordance with the general scheme set forth in the drawing, that is, the cyan dye developer/red-sensitive emulsion unit next contiguous the support surface and the yellow dye developer/blue-sensitvie emulsion unit most distant from the support surface.

As detailed in the illustrative drawing, a selectively exposed photosensitive element 25 comprises: a support a layer 11 containing a cyan dye developer; a layer 12 comprising a red-sensitive silver halide emulsion; an interlayer 13 formulated as detailed above; a layer 14 containing a magenta dye developer; a layer 15 comprising a green-sensitive silver halide emulsion; an interlayer 16 formulated as detailed above; a layer 17 containing a yellow dye developer; a layer 18 comprising a blue-sensitive silver halide emulsion; and a protective overcoat layer 19.

As shown in the drawing, the multilayer exposed photosensitive element 25 is shown in processing relationship with an image-receiving element 26 and a layer 20 of processing composition distributed intermediate elements and 26.

Image-receiving element 26 comprises: a support 24; a neutralizing layer 23; a spacer layer 22; and an imagereceiving layer 21.

As previously discussed, liquid processing composition 20 is eifective to initiate development of the latent images in the respective silver halide emulsion strata and hydration of the polymeric interlayers. After a suitable imbibition period, during which at least a portion of the dye developer associated with unexposed areas of each of the emulsions is transferred to superposed image-receiving element 26, the latter element is separated to reveal the positive multicolor image.

The present invention will be illustrated in greater detail in conjunction with the following procedures which set out representative embodiments and photographic utilization of the novel photosensitive elements of this invention, which, however, are not limited to the details therein set forth and are intended to be illustrative only.

A control photosensitive element similar to that shown in the drawing, denoted hereinafter as coating No. I, was prepared by coating on a gelatin subbed cellulose triacetate film base, the following layers;

(1) A layer of the cyan dye developer 1,4-bis-(5-[hydroquinonyl methyl]-ethylamino)-5,8-dihydroxy-anthraquinone dissolved in diethyl lauramide, dispersed in gelatin and coated at a coverage of 159 mgsJft. of dye and 119 mgs./ft. of gelatin.

(2) A red-sensiitve gelatino-silver iodobromide emulsion containing 4'-methylphenyl hydroquinone coated at a coverage of 222 rugs/ft. of silver, 15 mgs./ft. of 4'- methylphenyl hydroquinone, and 137 mgs./ft. of gelatin.

(3) A layer of vinyl acetate-orotonic acid copolymer comprising 2%, by weight, crotonic acid, coated at a coverage of 180 mgs./ft.

(4) A layer of the magenta dye developer Z-(p-[ozhydroquinonylethyl]-phenylazo) 4 isopropoxy 1- naphthol, dissolved in diethyl lauramide, dispersed in gelatin and coated at a coverage of 65 mgs./ft. of dye and 97 rugs/ft. of gelatin.

(5) A green-sensitive gelatino-silver iodobromide emulsion coated at a coverage of 108 rugs/ft. of silver and 68 mgs./ft. of gelatin.

(6) A layer of gelatin coated at a coverage of mgs./ft.

(7) A layer of the yellow dye developer 4-(p-[B-hydroquinonylethyH-phenylazo 3 (N-n-hexylcar'boxamido)- l-phenyl-S-pyrazolone, dissolved in diethyl lauramide dispersed in gelatin and coated at a coverage of 55 mgs./ ft. of dye and 69 rngs./ft. of gelatin.

(8) A blue-sensitive gelatino-silver iodobromide emulsion coated at a coverage of 61 mgs./ft. of silver and 46 mgs./ft. gelatin; and

(9) A layer containing 4'-methyl-phenyl hydroquinone dissolved in diethyl lauramide, disperse-d in gelatin and coated at a coverage of 10 mgs./ft. of 4-methylphenyl hydroquinone and 30 mgs./ft. of gelatin.

A second control photosensitive element, denoted hereinafter as Coating No. II, was prepared according to the procedure employed for the preparation of Coating No. I except that layer 1 additionally contained mucochloric acid coated at a coverage of 4 mgs./ft.

A first test photosensitive element, denoted hereinafter as Coating No. III, was prepared according to the procedure employed for the preparation of Coating No. I except that layer 3 additionally contained succindialdehyde coated at a coverage of 15 mgs./ft.

A second test photosensitive element, denoted hereinafter as Coating No. IV, was prepared according to the procedure employed for the preparation of Coating No. II except that layer 3 additionally contained succindialdehyde coated at a coverage of 15 mgs./ft.

A third test photosensitive element, denoted hereinafter as Coating No. V, was prepared according to the procedure employed for the preparation of Coating No. I except that layer 3 additionally contained mucochlon'c acid coated at a coverage of 4 mgs./ft. and succindialdehyde coated at a coverage of 15 mgs./ft.

The required number of image-receiving elements were prepared by coating a cellulose nitrate subcoated baryta paper with the partial butyl ester of polyethylene/maleic anhydride copolymer prepared by refluxing, for 14 hours, 300 grams of high viscosity poly-(ethylene/maleic anhydride), 140 grams of n-butyl alcohol and 1 cc. of 85% phosphoric acid to provide a polymeric acid layer approximately 0.75 mil thick. The external surface of the acid layer was coated with a 4% solution of polyvinyl alcohol in water to provide a polymeric spacer layer approximately 0.3 mil thick. The external surface of the spacer layer was then coated with a 2:1 mixture, by weight, of polyvinyl alcohol and poly-4-vinylpyridine, at a coverage of approximately 600 mgs./ft. to provide a polymeric image-receiving layer approximately 0.40 mil thick. The thus-prepared image-receiving element was then baked at F. for 30 minutes and then allowed to cool.

The photosensitive elements were then exposed and processed by spreading an aqueous liquid processing composition comprising:

between an individual image-receiving element and each of the exposed multicolor elements, as they were brought into superposed relationship in a Polaroid Land Camera. After an imbibition period of 1 minute, the picture door of the camera was opened and the image-receiving element separated from the remainder of the film assembly.

Examination of the resultant control and test transfer prints are summarized below:

image-receiving element may be spread apart from their superposed processing position during exposure. A camera apparatus suitable for processing film of the type just mentioned is provided by the Polarized Land Camera, sold by Polaroid Corporation, Cambridge, Massachusetts, or similar camera structure such, for example, as the roll film type camera forming the subject matter of U.S. Patent No. 2,435,717 or the film pack type camera Conditioning Maximum Transfer Dye Minimum Transfer Dye Fog Density Density Coating No.

'ilemp erla- Time Cyan Magenta Yellow Cyan Magenta Yellow 10 second 1 minute ure, 1

I 75 1 day..." 1. 46 1. 73 1.92 0. ()8 0. 09 0.11 0. 44 0. 80 75 6 days 1. 43 1. 76 1. 99 0.09 0.10 0. 13 0.42 0. 80 120 do 1.35 1. 67 1. 94 0.12 0.11 0.14 0.48 1.02

H 75 1 day-- 1. 39 1. 71 1. 85 0.04 0.07 0.09 0. 6O 1. 05 75 6 (183 5.... 1.18 1. 72 1. 94 0.04 0. 07 0.11 0. 44 0. 84 120 do 1.17 1.66 l. 92 0.04 0.07 0.11

III 75 1 day-.- 1. 74 1. 74 2.00 0.08 0.09 0.13 O. 40 0. 66 75 6 days 1. 75 1. 78 1. 99 0.07 0. 09 0.14 0. 40 0. 72 120 do 1. 77 1.76 1. 99 0.09 0.10 0.14 0.44 0.76

IV 75 1 day"-.- 1. 59 1. 80 2.00 0.04 0.07 0.12 0.50 0. 94 75 6 days- 1. 59 1. 77 1. 96 0.04 0.07 0.11 0. 42 0.80 120 do 1. 52 2. 69 1. 93 0.04 0.07 0. 11 0.52 0.94

V 75 1 day 1. 68 1. 73 2. 03 0.06 0.09 0. 14 0. 34 0. 66 75 6 days 1. 69 1. 74 2.01 0.06 0. 09 0.14 0. 40 0. 76 120 do 1. 72 1. 73 1. 98 0. 06 0. 09 0. 14 r .0. 52 0.88

and direct visual observation of improved color brilliance, hues, saturation, and isolation. Photographic and visual examination of exposed and processed photosensitive element microtome sections revealed decreased inter-image effects within the processed element fabricated in accordance with the instant invention, as compared with the control element.

It will be noted that the liquid processing composition employed may contain an auxiliary or accelerating developing agent, such as p-methylaminophenol, 2,4- diaminophenol, p-benzylaminophenol, hydroquinone, toluhydroquinone, phenylhydroquinone, 4-methylphenylhydroquinone, etc. It is also contemplated to employ a plurality of auxiliary or accelerating developing agents, such as a 3-pyrazolidone developing agent and a benzenoid developing agent, as disclosed in U.S. Patent No. 3,039,- 869, issued June 19, 1962. As examples of suitable combinations of auxiliary developing agents, mention may be made of 1-phenyl-3-pyrazolidone in combination with pbenzylaminophenol and l-phenyl-3-pyrazolidone in combination with 2,S-bis-ethylenimino-hydroquinone. Such auxiliary developing agents may be employed in the liquid processing composition or they may be initially incorporated, at least in part, in any one or more of the silver halide emulsion strata, the strata containing the dye developers, the interlayers, the overcoat layer, the image-receiving layer, or in any other auxiliary layer, or layers, of the film unit. It may be noted that at least a portion of the dye developer oxidized during development may be oxidized and immobilized as a result of a reaction, e.g., an energy-transfer reaction with the oxidation product of an oxidized auxiliary developing agent, the latter developing agent being oxidized by the development of exposed silver halide. Such a reaction of oxidized developing agent with unoxidized dye developer would regenerate the auxiliary developing agent for further reaction with the exposed silver halide.

In addition, development may be effected in the presence of an onium compound, particularly a quaternary ammonium compound, in accordance with the processes disclosed in the U.S. Patent No. 3,173,786, filed Mar. 16, 1965.

In products employed in the diffusion transfer processes of this invention, it is preferable to expose from the emulsion side. It is, therefore, desirable to hold the photosensitive element and the image-receiving element together at one end thereof by suitable fastening means in such manner that the photosensitive element and the forming the subject matter of U.S. Patent No. 2,991,702. Camera apparatus of this type permits successive exposure of individual frames of the photosensitive element from the emulsion side thereof as well as individual processing of an exposed frame by bringing said exposed frame into superposed relation with a predetermined portion of the image-receiving element while drawing these portions of the film assembly between a pair of pressure rollers which require a container associated therewith and efiect the spreading of the processing liquid released by rupture of said container, between and in contact 'with the exposed photosensitive frame and the predetermined, registered area of the image-receiving element.

It will be apparent that the relative proportions of the agents of the diffusion transfer processing composition may be altered to suit the requirements of the operator. Thus, it is within the scope of this invention to modify the herein described developing compositions by the substitution of preservatives, alkalies, silver halide solvents, etc., other than those specifically mentioned, provided that the pH of the composition is initially in excess of at least 10, for most favorable results, and most preferably in excess of 12. When desirable, it is also contemplated to include, in the developing composition, components such as restrainers, accelerators, etc. Similarly, the concentration of various components may be varied over a wide range and when desirable adaptable components may be disposed in the photosensitive element, prior to exposure, in a separate permeable layer of the photosensitive element and/ or in the photosensitive emulsion.

The support layers referred to may comprise any of the various types of conventional rigid or flexible supports, for example, glass, paper, metal, and polymeric films of both synthetic types and those derived from naturally occurring products. Suitable materials include paper; aluminums; polymethacrylic acid, methyl and ethyl esters; vinyl chloride polymers; polyvinyl acetal; polyamides such as nylon; polyesters such as polymeric films derived from ethylene glycol terephthalic acid; and cellulose derivatives such as cellulose acetate, triacetate, nitrate, propionate, butyrate, acetate-propionate, or acetate-butyrate.

The nature and construction of rupturable containers is well understood in the art; see, for example, U.S. Patent No. 2,543,181, issued Feb. 27, 1951, and U.S. Patent No. 2,634,886, issued Apr. 14, 1953.

It will be apparent that, by appropriate selection of the image-receiving element materials from among suitable known opaque and transparent materials, it is possible to 17 obtain either a colored positive reflection print or a colored positive transparency.

While a rupturable container provides a convenient means for spreading a liquid processing composition between layers of a film unit whereby to permit the processing to be carried out within a camera apparatus, the practices of this invention may be otherwise etfected. For example, a photosensitive element, after exposure in suitable apparatus and while preventing further exposure thereafter to actinic light, may be removed from such apparatus and permeated with the liquid processing composition, as by coating the composition on said photosensitive element or otherwise wetting said element with the composition, following which the permeated, exposed photosensitive element, still, without additional exposure to actinic light, is brought into contact with the imagereceiving element for image formation in the manner heretofore described.

In all examples of this specification, percentages of components are given by weight unless otherwise indicated.

Throughout the specification and appended claims, the expression positive image has been used. This expression should not be interpreted in a restrictive sense since it is used primarily for purposes of illustration, in that it defines the image produced on the image-carrying layer as being reversed, in the positive-negative sense, with respect to the image in the photosensitive element. As an example of an alternative meaning for positive image, assume that the photosensitive element is exposed to actinic light through a negative transparency. In this case, the latent image in the photosensitive element will be a positive and the image produced on the image-carrying layer -will be a negative. The expression positive image is intended to cover such an image produced on the image-carrying layer.

Throughout the specification and claims, the expression superposed has been used. This expression is intended to cover the arrangement of two layers in overlying relation to each other either in face-to-face contact or in separated condition and including between them at least a layer of fluid processing composition.

It also will be recognized that, where desired, the film unit structure may also comprise an integral positive/ negative construction carried on a single support.

In addition to the described essential layers, it will be recognized that the film unit may also contain one or more subcoats or layers, which, in turn, may contain one or more additives such as plasticizers, intermediate essential layers for the purpose, for example, of improving adhesion.

Since certain changes may be made in the above product and process without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What we claim is:

1. A a product, a photosensitive element which comprises, in combination, a support layer, at least two selectively sensitized gelatino silver halide emulsion layers each having a dye, which dye is a silver halide developing agent, of predetermined color associated therewith and a layer, intermediate said emulsion layers, comprising a processing composition permeable polymer containing a ditfusible gelatin hardening agent substantially inert with respect to said polymer.

2. As a product, a photosensitive element as defined in claim 1, wherein at least one of said dyes is disposed in a separate gelatin layer adjacent its associated silver halide emulsion layer.

3. As a product, a photosensitive element as defined in claim 1, wherein said hardening agent comprises succindialdehyde.

4. As a product, a photosensitive element as defined in claim 1, wherein said hardening agent comprises mucochloric acid.

5. As a product, a photosensitive element as defined in claim 1, wherein said polymer comprises a processing composition permeable and hydratable polymer having a dye permeable lattice substantially only in the hydrated state and hydration rate less than the development and greater than the fogging rate of the associated silver halide emulsion possessing the slowest development and most rapid fogging rate.

6. As a product, a photosensitive element as defined in claim 5, wherein said polymer comprises a vinyl acetatecrotonic acid copolymer having less than 5% crotonic acid, by weight.

7. As a product, a photosensitive element as defined in claim 5, wherein said polymer comprises isopropyl cellulose.

8. As a product, a photosensitive element as defined in claim 5, wherein said polymer comprises hydroxypropylmethyl cellulose.

9. As a product, a photosensitive element as defined in claim 1, wherein said photosensitive element comprises, as essential layers, a support layer carrying on one surface at least two selectively sensitized gelatino silver halide emulsions having predominant spectral sensitivity to separate regions of the spectrum and each having a dye associated therewith, which dye is a silver halide developing agent, having a spectral absorption range substantially complementary to the predominant sensitivity range of the associated emulsion, and a layer, intermediate at least two of said gelatino silver halide emulsion layers, comprising a processing composition permeable polymer containing a diffusible gelatin hardening agent substantially inert with respect to said polymer.

10. As a product, a photographic film unit as defined in claim 9, including a difiusion transfer image-receiving element affixed one edge of said photosensitive element, said diffusion transfer image-receiving element comprising, as essential layers, in sequence, a support layer, a polymeric acid layer, and a dyeable polymeric layer, and said photosensitive element and said image-receiving element adapted to be superposed with said gelatino silver halide emulsion, distant said support, positioned in overlying relationship with said dyeable polymeric layer.

11. As a product, a photographic film unit as defined in claim 10, including a rupturable container retaining an aqueous alkaline solution affixed one edge of said photosensitive and said image-receiving element and adapted upon rupture to distribute its retained contents intermediate said photosensitive element and said image-receiving element upon superpositioning of said elements.

12. As a product, a photographic film unit as defined in claim 11, wherein said aqueous alkaline solution has a pH of not less than about 12.

13. As a product, a photographic film unit as defined in claim 8, wherein each of said dyes is disposed in a separate gelatin layer adjacent its associated gelatino silver halide emulsion layer next adjacent said support layer.

14. As a product, a photosensitive element as defined in claim 13, wherein said gelatino silver halide emulsion layers have a thickness less than about 3 microns, said separate gelatin layers retaining said dyes have a thickness less than about 5 microns and said polymer layer has a thickness less than about 3 microns.

15. As a product, a photographic film unit, as defined in claim 9, which comprises, in combination, a photosensitive element containing a plurality of essential layers including, in sequence, a support, a cyan dye-containing gelatin layer, a red-sensitive gelatino silver halide emulsion layer, a spacer layer, a magenta dye-containing \gelatin layer, a green-sensitive gelatino silver halide emulsion layer, a spacer layer, a yellow dye-containing gelatin layer, and a blue-sensitive gelatino silver halide emulsion layer, each of said cyan, magenta and yellow dyes "being silver halide developing agents, and at least one of said spacer layers comprising a processing composition permeable polymer retaining a difiusible gelatin hardening agent substantially inert with respect to said polymer, each of said gelatino silver halide emulsion layers less than about 3 microns thick, each of said dye-containing gelatin layers less than about 5 microns thick and said polymer layer less than about 3 microns thick, and wherein the sum total thickness of all of said layers taken together is less than 30 microns,

. 16. A process of forming transfer images in color which comprises the steps of exposing a photosensitive element comprising at least two, selectively sensitized gelatino silver halide emulsion strata, each of said gelatino silver halide emulsions having associated therewith a dye, which is a silver halide developing agent, of predetermined color, and a layer intermediate at least two of said gelatino silver halide emulsion strata, comprising a processing composition permeable polymer containing a diffusible gelatin hardening agent substantially inert with respect to said polymer; applying an aqueous alkaline processing composition to said exposed photosensitive element; etfectin g development of the latent images contained in each of said silver halide emulsions; immobilizing the dye associated with each of said emulsions as a result of development; forming an imagewise distribution of mobile dye, as a function of the point-to-point degree of exposure thereof; and transferring, by imbibition, at least a portion of each of said imagewise distributions of mobile dye to a superposed image-receiving layer to provide thereto a multicolor dye image.

17. A process of forming multicolor transfer images, as defined in claim .16, which comprises the steps of exposing a photosensitive element which includes bluesensitive, green-sensitive and red-sensitive gelatino silver halide emulsion layers, each of said emulsion layers less than about 3 microns thick and mounted on a common support, said blue-sensitive, green-sensitive and red-sensitive gelatino silver halide emulsions having associated therewith, respectively, yellow, magenta and cyan dyes, each of said dyes being a silver halide developing agent and being dispersed in a separate layer, less than about 5 microns thick, comprising gelatin, next adjacent its associated emulsion intermediate said emulsion and said support, at least two of said emulsion and associated dyecontaining layers having, intermediate same, a layer less than about 3 microns thick comprising an alkali solution permeable polymer retaining a difiusible gelatin hardening agent substantially inert with respect to said polymer; applying an aqueous alkaline processing composition to said exposed photosensitive element; effecting development of the latent images contained in said emulsions; immobilizing said yellow, magenta and cyan dye, as a result of development of the exposed areas of their associated silver halide emulsions; forming thereby an imagewise distribution of mobile yellow, magenta and cyan dye, in unexposed areas of their associated emulsions, as a function of the point-to-point degree of emulsion exposure; and transferring, by imbibition, at least a portion of each of said imagewise distributions of dyes to a superposed image-receiving layer to provide thereto a multicolor dye image.

References Cited NORMAN G. TORCHIN, Primary Examiner.

G. COHN, Assistant Examiner.

- US. Cl. X.R. 96-76 

1. A PRODUCT, A PHOTOSENSITIVE ELEMENT WHICH COMPRISES, IN COMBINATION, A SUPPORT LAYER, AT LEAST TWO SELECTIVELY SENSITIZED GELATINO SILVER HALIDE EMULSION LAYERS EACH HAVING A DYE, WHICH DYE IS A SILVER HALIDE DEVELOPING AGENT, OF PREDETERMINED COLOR ASSOCIATED THEREWITH AND A LAYER, INTERMEDIATE SAID EMULSION LAYERSS, COMPRISING A PROCESING COMPOSITION PERMEABLE POLYMER CONTAINING A DIFFUSIBLE GELATIN HARDENING AGENT SUBSTANTIALLY INERT WITH RESPECT TO SAID POLYMER. 